Polymethine dyestuffs



Patented Apr. 2, 1940 UNITED STATES PATENT OFFICE POLYMETHINE DYESTUFFS No Drawing. Application May 10, 1937, Serial No. 141,866. In Germany May 9, 1936 Claims.

(Granted under the provisions of sec. 14, act of March 2, 1927; 357 0. 5)

The present invention relates to new polymethine dyestufls.

The new polymethine dyestulis are characterized by their containing up to two quinoxaline 5 radicals which are attached in the 2-position to the polymethine chain, and which are substituted in the 3-position by alkyl, aryl or aralkyl and in the l-position by any radical, as for instance by alkyl, hydroxyalkyl, chloroalkyl, sulfoalkyl, aralkyl, acyl or aryl. This definition also includes cases in which one quinoxaline radical,

substituted as mentioned above, is attached in the 2-position to the polymethine chain and linked by means of this polymethine chain with an aromatic radical or a heterocyclic radical,

other than quinoxaline, containing auxochromic groups. The above nomenclature is based upon the following scheme:

5 4 N e os 7 oz s 1 The new dyestuffs are obtained from 2-methylene-quinoxalines of the formula:

wherein :1: stands for one of the substituents in the 3-position and y for one of the substituents in the 1-position as mentioned above and R stands for an aromatic radical, such as a benzene or a naphthalene nucleus, which can be substituted for instance by alkyl, alkoxy, halogen, the nitro group, the amino group, the sulfo group and so on, or the salts of these 2-methylenequinoxalines, and these Z-methyIene-quinoxalines or the salts thereof are converted into the polymethine dyestuflfs by methods ordinarily scheme: 5

N NH: 00 CH on;

s +2H,o lTTH OC-CH; N oH, 0 5 I I 20 The 2-methylenequinoxalines substituted in the 1-position can partly also be obtained from the easily obtainable corresponding 2.3-dimethylquinoxaline by reaction with alkyl halides, for instance, according to the following equation:

The Z-methylenequinoxalines used as starting material are somewhat unstable. It has, there- 35 fore, proved in many cases to be of advantage not to isolate these derivatives, but to carry out one process only in which is contained the reaction leading from the N-monosubstituted odiamine to the quinoxaline and the immediate 40 condensation of the latter.

The polymethine dyestufis according to the present invention are generally well crystallizing substances and are distinguished by an excellent clearness, strength of color and a good 45 aflinity, and yield on cotton mordanted with tannic acid, silk, artificial silk, cellulose ethers, cellulose esters in general blue to green shades. The dyeings are fast to alkali and acid and are partly of a good dischargeability, especially on acetate silk. Further the new dyestufis act as strong desensibilizers for the photographic layer.

The invention is illustrated by the following examples, but is not restricted thereto, the parts beingby weight:

Example 1 30 parts of N-phenyl-Z-methylene-3-methylquinoxaline are stirred in 60 parts of acetic acid anhydride with 30 parts of sodium. formiate at 30 C. for 24 hours, the deep green solution is mixed with water, freed from minor quantities of resin and then precipitated with sodium chloride. The dyestuif which corresponds to the following formula:

is obtained in fine needles of golden luster. It represents the symmetric polymethine dyestufi prepared from 2 molecular proportions of the mentioned quinoxaline connected by a chain consisting of three CH-radicles, and dyes cotton and silk clear greenish shades.

Example 2 One molecular proportion of N-phenyl-Z- methylene-3-methylquinoxaline is condensed in acetic acid anhydride with one molecular proportion of 1.3.3-trimethylindoline-2-methylene-w aldehyde at 30 C. during 6 hours. An asymmetric polymethine dyestuff is thus obtained. The solution is poured into water, freed from the resin and precipitated with sodium chloride. The dyestufi is obtained in fine needles; the salt is water-soluble. The dyestuff, which corresponds to the following formula:

Cl CH:

dyes cotton, silk and acetate artificial silk clear, pure blue shades. It is fast to acid and alkali and dischargeable on acetate artificial silk. The discharges are fast to light.

Emample 3 One molecular proportion of the quinoxaline derivative mentioned in Example 1 is condensed in acetic acid anhydride with one molecular proportion of 4-diethyl-amino-benzaldehyde during 24E hours at 30 C. and Worked up in the same manner as stated in the preceding examples. A

bluish-green dyestuff is obtained, which corresponds to the following formula:

\ly-ons o-on=on n can),

Example 4 One molecular proportion of N-methyl-2- methylene-3-methylquinoxaline is condensed with one molecular proportionof the aldehyde described in Example 2. A dyestufi is obtained of a very high dyeing strength; it dyes a reddish blue. The dyestuff corresponds to the following formula:

ocii; (CHIOFF' o-cn=onon CH: Cl CH3 Example 5 30 parts of N-methyl-2-methylene-3-methylquinoxaline are stirred in 60 parts of acetic acid anhydride at 30 C. for 24 hours with 30 parts of sodium formiate. A green dyestuff, the symmetric polymethine dyestuif, is obtained which corresponds to the following formula:

N N \3-011.1 Ulla-0 C Hr, Cl C H:

and which dyes clear green shades.

Example 6 One molecular proportion of N-sulfoethyl-2- methylene-3-m.ethylquinoxaline is condensed with one molecular proportion of the aldehyde mentioned in Example 2 in the same manner as described in this example. The dyestuff obtained which corresponds to the following formula:

AV c om (CHQ):=""

and which dyes a clear blue.

Example 8 One molecular proportion of N-phenyl-SZ- methylene-3methyl-6-chloroquinoxaline is condensed with one molecular proportion of the aldehyde mentioned in Example 2 in the manner described there. A greenish Well crystallizing dyestuff is obtained dyeing a very clear greenishall blue. The dyestufi corresponds to the following formula:

l 01 CHI Example 9 One molecular proportion of N-(p-ethoxy 'phenyl)-2-methylene 3 methyl-G-aminoquinoxaline is condensed with one molecular proportion of the aldehyde mentioned in Example 2 in the manner described there; at the same time acetylation of the 6-amino group takes place and a well crystallizing dyestuff is obtained which dyes a clear deep blue, and which corresponds to the following formula:

Example 11 One molecular proportion of 2.3'-.dimethylquinoxalineis caused to react upon one molecular proportion of methyl iodide at 60 C. The 1.2.3-trimethylquinoxalinium iodide thus obtained is finely powdered and added to a solution of one molecular proportion of 1.3.3-trimethylindoline 2 methylene-w-aldehyde. The formation of the dyestuff takes already place in the cold and is complete after 6 hours at 35 C. The dyestuff corresponds to the following formula:

OCH=CH-CH=\N/ I OH:

on" I We claim:

1. Polymethine dyestuffs of the general formula: RCH=CH-CH=R1 wherein R stands for a quinoxaline radical and R1 for one of the radicals of the group consisting of quinoxaline radicals and 1.3.3-trialklyindoline radicals, these radicals being attached in the 2-po-' sitionto the trimethine chain, and'the quinoxaline radicals either the l-N of the quinoxaline or of the indoline being quaternary are substituted in the 3-position by an alkyl radical and in the 1-position by a member of the group consisting of alkyl, sulfoalkyl, benzyl and mononuclear aromatic radicals. I

2. Polymethine dyestuffs as claimed in claim 1 in Which'the quinoxaline radicals are substituted in the 3-position by a methyl radical.

3 Polymethine dyestuffs as claimed in claim- 1 in which the quinoxaline radicals are substituted in the 3-position by a methyl radical and in the l-position by a phenyl radical. 4. The polymethine dyestuff of the formula:

WERNER MULLER. OTTMAR WAHL. ERNST TEUPEL.

CERTIFICATE OF CORRECTION.

Patent No. 2,196,162. April 2, 191m.

WERNER HELLER, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, fir st column, lines to 5].]. inclusive, in the formula, for "-CN:CH-CH:" read -CH CHCH: page 5, second column, line 15, claim 1, for "1.5.5- trialklyindoline" read -l.5.5-trialkylind0line and that the said Letters Pateht should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 17th day of September, A. 191w.

\ Henry Van Arsdale, (Seal) Acting Commissioner of Patents 

